Controlled release suture

ABSTRACT

A needle-suture combination having a suture pull-out value in the range of 1 to 26 ounces is manufactured by applying sufficient tension to the suture to move it relative to the needle barrel and releasing the tension when the force drops to within the following range for that size of suture:Suture Size Ounces ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 8/0 1. - 2. 7/0 1. - 3. 6/0 2. - 5. 5/0 3. - 7. 4/0 5. - 15. 3/0 5. - 23. 2/0 5. - 26. 1/0 10. - 26. 1 10. - 26. 2 and larger 10. - 26. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I United States Patent 1 [ll] 3,875,946

Duncan Apr. 8, 1975 CONTROLLED RELEASE SUTURE [57] ABSTRACT [75]Inventor: Robert Barclay Duncan, Somerville. A needle-suture combinationhaving a suture pull-out N value in the range of l to 26 ounces ismanufactured by applying sufficient tension to the suture to move it[73] Assgnee' Eamon Somervme' relative to the needle barrel andreleasing the tension [22] Filed: Feb. 27, 1974 when the force drops towithin the following range for 1 pp No: 446,174 that size of suture:

[52} US. Cl. 128/339; 128/335.5; T6331}; suture size ounces [5 I] Int.Cl A6lb 17/06 8/0 I. 2. 581 Field of Search 128/3355, 339, 334 R; 335:12; 163/5, I; 223/l02 5/0 3. 7. :13 [56] References Cited 2/0 5: I SeiUNITED STATES PATENTS {31 5;; 2,240,330 4/194] Flugg et ul. l28/339 2and "2" we 2.620.028 l2/l952 Kohut 163/5 2910.983 11/1959 Everettl28/339 3.799.l69 3/1974 Beroff et l28/339 Primary Examiner-Dalton L.Truluck Claims n Drawing Figures Attorney, Agent, or Firm-Wayne R.Eberhard! PATENTEUAPR ems SHLEI 1 [if 4 SHEEI 3 (IF 4 PATENTEU 8|975CONTROLLED RELEASE SUTURE BACKGROUND OF THE INVENTION In many surgicalprocedures, surgeons use a tech- 5 nique which employs a non-needledsuture and an eyed needle. The needle is threaded by the nurse and thesurgeon takes one pass through the tissue using a needleholder. He slipsthe needle off the suture, returns the needle to the nurse, and is readyfor another threaded needle from the nurse. An assistant follows behindand ties the suture.

Surgeons find that this technique is more simple than using a needleditem and cutting the suture with a scissors after each pass. However,the time required for threading results in a significant waste ofexpensive operating room time.

The security of attachment of eyeless needles to absorbable surgicalsutures or to nonabsorbable surgical sutures is prescribed in the U.S.Pharmacopoeia, Vol. XVIII at Page 944 (also see U.S. Pharmacopoeia, Vol.XVII, Page 919). It has been the practice of suture manufacturers in theUnited States and abroad to securely attach the suture to the needle byswaging or with an adhesive so that the minimum pull'out standardrecited in the U.S. Pharmacopoeia is met or exceeded. The conversion ofthe U.S. Pharmacopoeia minimum standard on needle attachment fromkilograms to ounces is summarized in the following table.

TABLE I MINIMUM LIMITS ON NEEDLE ATTACHMENT Average Ounces 2 and largerIt will be noted from the above table that separation of the suture fromthe needle is relatively easy if the suture is size 5/0 or smaller sincethe average force required is less than 8 ounces. On the other hand, theminimal average force required to separate a size 4/0 suture (diameter7.0 mils to 9.5 mils) from the needle is about l6 ounces and becauseneedles are swaged to make quite certain that the minimum U.S.Pharmacopoeia standards are met, many individual samples require forcesin excess of 2 pounds to detach the needle from the suture.

There is a need for a needle-suture combination that has the convenienceof the needle being preattached to the suture and yet permits separationof the needle from the suture without the necessity of cutting with ascissors.

One approach to this problem is described in copending application Ser.No. 252,l76, filed May II, 1972, now U.S. Pat. No. 3,799,169. Thisapproach involves manufacturing the needle with an open channel at theblunt end thereof sized to receive a suture. The suture is bonded to thechannel with an adhesive that prevents pull-out of the suture as itpasses through tissue. After suturing, the surgeon may easily remove theneedle from the suture by turning the needle so that the channel is atan angle of about to the direction of the suture and peeling the sutureout of the channel.

This approach has one disadvantage in that many surgeons prefer a closedchannel over an open channel needle because of the uniform cross'sectionat the end of the needle and the smooth transition between the needleand the attached suture.

[t is an object of the present invention, therefore, to make availableto the surgeon a needle-suture combination useful in suturing, andcharacterized by a needle-suture attachment that will permit facileremoval of the needle from the suture without cutting the suture with ascissors.

Another object of this invention is to provide the surgeon with aneedle-suture combination that will reduce the time that the surgicalpatient must spend in the operating room.

Yet another object of the invention is to provide the surgeon with aneedle-suture combination that will permit separation of the needle fromthe suture after suturing by a slight pull upon the needle.

SUMMARY OF THE INVENTION Needle-suture combinations manufactured inaccordance with the present invention are characterized by a suturepull-out value substantially lower than the minimum average forcespecified in the U.S. Pharmacopoeia. The process of the presentinvention permits better control of the end product in that the forcerequired to separate a suture of a particular size from its attachedneedle is uniform. Thus, in any batch of needled sutures manufacturedduring a single production run, the variation of the pull-out value fromthe mean is reduced.

It is an advantage of the product of the present invention, therefore,that the surgeon may readily remove the needle from the suture byexerting a force less than that specified in Table I and thereby savethe time previously required to cut the suture. The actual forcerequired to remove the needle from the suture will vary with the suturesize, but can be controlled within the following limits by the method tobe described.

It will be noted from the above table that the pullout" range is lowerthan that specified in the U.S. Pharmacopoeia and in no instance exceedsabout 26 ounces.

The suture utilized in the present invention may be any known braided ormonofilament suture materials, either absorbable, i.e., catgut, extrudedcollagen, a braided polyhydroxyacetic ester, a synthetic copolymer ofL(-) lactide and glycolide', or non-absorbable, i.e., silk, nylon,polypropylene, cotton, linen, or polyester.

The needled sutures of the present invention are manufactured byconventional procedures. One end of a suture is inserted into a drilledneedle, a channel needle or a preclosed channel needle and the needle isswaged to secure the suture. It has long been known that by propercontrol of the diameter of that end of the suture which is placed in theneedle, the diameter of the needle hole and the swaging process, needledsutures can be manufactured that satisfy the minimum limits on needleattachment as set forth in the U.S. Pharmacopoeia.

It is also known that in swaging, excess force is to be avoided asover-swaging will weaken the suture strand and result in the suturebreaking at the needle. In accordance with the present invention, theneedled sutures are swaged so that the force required to pull the sutureout of the needle exceeds the minimum limits on needle attachment setforth in Table I, but is less than the actual tensile strength of thesuture used.

Preferably, the needles are swaged so that the suture may be pulled outof the needle by a force in the range of l to 6 pounds for size 4/0suture and larger. If the suture is smaller than size 4/0, it ispreferred that the needle be swaged so that the suture may be pulled outof the needle without breaking by a force in the range of 3 to ounces asindicated in the following table.

TABLE III Force in Ounces Required to Move Suture Relative Suture Sizeto the Needle Barrel The pull-out characteristics that distinguish theproduct of the present invention are obtained by prestressing thesuture, i.e., tension is applied to the suture after the swaging steppartially pulling the suture out of the needle. As the suture is pulledfrom the needle, the force required to move the suture relative to theswaged section decreases. When the force required to move the end of thesuture relative to the needle barrel drops to the desired pull-outvalue, the tension is released.

It has been noted that if the bond between the needle and its attachedsuture is within the range set forth in Table II, the suture will notseparate from the needle as the surgeon passes the needle throughtissue. Yet, the needle can easily be removed from the suture at anytime by simply pulling on the needle with a force of from I to about 26ounces depending upon the suture size. Needle-suture combinations havingthe pull-out values summarized in Table II may be manufactured byapplying sufficient tension to the suture to move it relative to theneedle barrel, and then releasing the tension when the force drops towithin the following range for that size of suture.

-Continued Suture Size Ounces 3/0 5 23. 2/0 5. 26. [/0 l0. 26. l 10. 26.2 and larger 10. 26.

The invention will appear more clearly from the following detaileddescription when taken in connection with the accompanying drawingswhich show by way of example preferred embodiments of the inventiveidea.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged perspective viewof a swaged and stressed needle-suture combination;

FIG. 2 is an enlarged perspective view of the needlesuture combinationof FIG. 1 and illustrates removal of the needle from the suture;

FIG. 3 is an enlarged sectional view of a needlesuture combination;

FIG. 4 is an enlarged sectional view of the needlesuture combination ofFIG. 3 showing displacement of the suture from the needle;

FIG. 5 is a diagram of apparatus useful in manufacturing the needledsutures of the present invention;

FIG. 6 is a graph of the displacement of a suture from the drilled holeas a function of the stress applied to the suture;

FIG. 7 is a graph of the displacement of a suture from the drilled holeas a function of the stress applied to the suture;

FIG. 8 is a graphic representation of the pull-out values determined oneleven prestressed needle-suture combinations;

FIG. 9 is a graph of the displacement of a suture from the needle holeas a function of the stress applied;

FIG. 10 is a graph of the displacement of a suture from the needle holeas a function of the stress applied;

FIG. 11 is a graphic representation of the pull-out values determined onten needle-suture combinations.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In accordance with the presentinvention, needled sutures are manufactured in the conventional mannerand prestressed to reduce the force required to separate the needle fromthe suture to a predetermined value. The resulting controlled releasesuture is then packaged and sterilized.

Prestressing may be accomplished by the apparatus illustrated in FIG. 5,which is designed to apply a stress to a needle 11 and the attachedsuture 12 sufficient to partially withdraw the suture from the needle.It includes in part an arm 13 fitted with a gate 14 sized to retainstationary the needle while permitting movement of the suture relativethereto. The arm is pivoted for movement around the pivot pin 15. Aclamp 16 fitted with movable jaws l7 and 17' is aligned with the gateand grips the suture. Movement of the clamp in the direction of thearrow applies stress to the suture causing it to move relative to theneedle barrel 30 thereby displacing the end 18 of the suture from thebottom 20 of the needle hole by a distance 19 (see FIGS. 3 and 4).

The stress applied to the suture by the clamp is monitored by a forcetransducer 21 which acts with the clamp to stop the movement thereofwhen the applied stress drops to a predetermined value.

FIG. 6 illustrates the relationship between stress, strain, and theactual displacement of four size 0 black braided silk sutures as tensionis applied to pull the sutures completely out of the needle. The suturesare swaged to a 39 mil drilled needle. The diameter of the drill hole is19 mils and the depth of the drill hole (the length of the suture withinthe needle barrel) is 70 mils.

F IG. 7 illustrates the relationship between stress, strain, and theactual displacement of four size 0 black braided silk sutures as tensionis applied to pull the sutures out of the needle. The sutures are swagedto a 39 mil drilled needle. The diameter of the drill hole is 19 milsand the depth of the drill hole (the length of the suture within theneedle barrel) is 70 mils. In this instance, the sutures are not pulledcompletely out of the needle; when the tension drops to 1 pound, themovement of the clamp is stopped.

FIG. 9 illustrates the relationship between stress, strain, and theactual displacement of a size 0 polyester suture from a channel needle.The needle is made of 39 mil wire and has a channel length (prior toclosure) of 178 mils.

As tension is applied to the suture by the clamp, the suture iselongated (about 0.02 inches) until the stress exceeds 6 pounds. At thatpoint, the suture moves relative to the needle and the stress drops asthe suture is withdrawn. Movement of the clamp is stopped when thestress reaches l pound at which point the displacement of the suturefrom the end of the needle channel is about 0.09 inches (about 50%displacement).

FIG. 10 depicts the relationship of stress, strain, and suturedisplacement when force is applied to a size 0 polypropylene sutureswaged to a channel needle. The needle is made of 39 mil wire and has achannel length (prior to closure) 188 mils. In this instance, as thestress is increased to about 4 pounds, the suture is stretched about0.02 inches. Increasing the stress above 4 pounds results in movement ofthe suture relative to the needle channel. Stress is removed when theforce applied drops to l pound at which point the suture has beendisplaced from the channel needle a distance of about 0.08 inches (about42% displacement).

The following examples will serve to further illustrate the invention.

EXAMPLE 1 Size 0 black braided silk suture strands are swaged to drilledneedles manufactured of 39 mil wire and having a drilled hole in theblunt end l9 mils in diameter and 70 mils deep. The suture ends areinserted into the needles until they are in contact with the bottom ofthe drilled hole as shown in FIG. 3. The needles are then swaged so thatthe force required to pull out the suture is within the range of aboutfrom 2 to 5 pounds.

The swaged needle-suture combinations are prestressed in a Table ModellNSTRON Tensile Tester (Model TT-DL) using a Type CT Tension Cell(fullscale range 100 pounds), and the machine is set so that full-scaledeflection is obtained at 20 pounds. Two line contact jaws are used tosecure the needled sutures in the lNSTRON machine. The upperjaw gripsthe needle and the lower jaw grips the suture about 0.25 inches belowthe needle. Both jaws are closed under 20 p.s.i. air pressure. ThelNSTRON machine is operated at a cross-head speed of 0.] inches perminute and a chart speed of 5 inches per minute until the tension dropsto one pound.

Ten prestressed needle-suture combinations randomly selected from thisproduction batch are replaced in the lNSTRON machine and stressed topull the suture out of the needle. The pull-out value for each of theten sutures is recorded below:

l4 ounces l4): ounces l3 ounces l3): ounces l4 ounces ll ounces 14ounces 15 ounces 16% ounces [5 ounces The narrow distribution ofpull-out values is graphically illustrated in FIG. 1 1.

EXAMPLE 2 Size 0 monofilament polypropylene suture strands are swaged todrilled needles manufactured of 39 mil wire and having a drilled hole inthe blunt end 19 mils in diameter and mils deep. The ends are insertedinto the needles until they are in contact with the bottom of thedrilled hole as shown in FIG. 3. The needles are swaged so that theforce required to pull the suture out of the needle is within the rangeof from about 3 to 5 pounds.

The swaged needle-suture combinations are prestressed in a Table ModellNSTRON Tensile Tester (Model TT-DL) using a Type CT Tension Cell(fullscale range pounds), and the machine is set so that full-scaledeflection is obtained at 20 pounds. Two line contact jaws are used tosecure the needled sutures in the lNSTRON machine. The upper jaw gripsthe needle and the lower jaw grips the suture about 0.25 inches belowthe needle. Both jaws are closed under 20 p.s.i. air pressure. ThelNSTRON machine is operated at a cross-head speed of 0.1 inches perminute and a chart speed of 5 inches per minute until the tension dropsto l pound.

Eleven prestressed needle-suture combinations randomly selected fromthis production batch are replaced in the lNSTRON machine and stressedto pull the suture out of the needle. The pull-out value for each of thel l sutures is recorded below:

17% ounces 16 ounces 17% ounces 16 ounces 17 ounces l7 ounces 17 ouncesl7 ounces l ounces l7 ounces l8 ounces The narrow distribution of thepull-out values is graphically illustrated in FIG. 8.

EXAMPLE 3 A size 2 black braided silk suture strand is swaged to achannel needle manufactured of 39 mil wire. The length of the channel(the length of the suture within the needle barrel) is seventhirty-seconds inches. The needles are swaged so that the force requiredto pull out the suture is about 5 pounds.

The swaged needle-suture combination is prestressed in a Table ModellNSTRON Tensile Tester as described in Example 1 above, until thetension required to pull the suture from the needle drops to 21 ounces.

Ten prestressed needle-suture combinations randomly selected from thisproduction batch are replaced in the INSTRON machine and stressed topull the suture out of the needle. The pull-out value for each of the 10sutures is recorded below:

l4 ounces l7 ounces l5 ounces l8 ounces 22 ounces 2] ounces l4 ounces 20ounces l6% ounces 26 ounces EXA M PLE 4 A size 1 black braided silksuture strand is swaged to a drilled needle manufactured of 32 mil wireand having a drilled hole in the blunt end 22 mils in diameter and 70mils deep. The end of the suture is inserted into the needle until it isin contact with the bottom of the drilled hole as shown in FIG. 3. Theneedle is then swaged so that the force required to pull the suture outof the needle is within the range of about from 3 to 6 pounds.

The swaged needle-suture combination is then prestressed in a TableModel INSTRON Tensile Tester (Model TT-DL) using a Type CT Tension Cell(fullscale range 100 pounds), and the machine is set so that full-scaledeflection is obtained at 20 pounds. Two line contact jaws are used tosecure the needled suture in the INSTRON machine. The upper jaw gripsthe needle and the lower jaw grips the suture about 0.25 inches belowthe needle. Both jaws are closed under 20 p.s.i. air pressure. TheINSTRON machine is operated at a cross-head speed of 0.1 inches perminute and a chart speed of 5 inches per minute until the tension dropsto 20 ounces.

Ten prestressed needle-suture combinations randomly selected from thisproduction batch are replaced in the INSTRON machine and stressed topull the suture out of the needle. The pull-out value for each of the isutures is recorded below:

15 ounces 20 ounces 16 ounces 24 ounces 15 ounces 2l ounces 1% ounces l9ounces 16% ounces 22 ounces EXAMPLE Size 3/0 black braided silk suturestrands are swaged to channel needles manufactured of 22 mil wire andhaving a channel in the blunt end five thirty-seconds inch in length(five thirty-seconds inch suture engagement). The needles are swaged toclose the channel so that the force required to pull out the suture iswithin the range of about from 1 to 2 pounds.

The swaged needle-suture combinations are prestressed in a Table ModelINSTRON Tensile Tester as described above until the tension drops to l 1ounces.

Ten prestressed needle-suture combinations randomly selected from thisproduction batch are replaced in the INSTRON machine and stressed topull the suture out of the needle. The pull-out value for each of the IDsutures is recorded below:

ll ounces l2 ounces 8 ounces 8 ounces 7 ounces 9 ounces l ounces 8ounces l3 ounces 7 ounces EXAMPLE 6 Size 4/0 black braided silk suturestrands are swaged to channel needles manufactured of 17 mil wire(suture engagement nine sixty-fourths inches). The needles are swaged sothat the force required to pull out the suture is about 1 pound.

The swaged needle-suture combinations are prestressed in a Table ModelINSTRON Tensile Tester as described in Example 1 above until the tensiondrops to 8 ounces.

Ten prestressed needle-suture combinations randomly selected from thisproduction batch are replaced in the INSTRON machine and stressed topull the suture out of the needle. The pull-out value for each of the 10sutures is recorded below:

6% ounces 6 ounces 9 ounces 7% ounces 8 ounces 9 ounces 6 ounces 7ounces 6% ounces 6 ounces EXAMPLE 7 Size 5/0 black braided silk suturestrands are swaged to channel needles manufactured of 14 mil wire(channel engagement seven sixty-fourths inch). The needles are swaged sothat the force required to pull out the suture is within the range of 7to 15 ounces.

The swaged needle-suture combinations are prestressed in a Table ModellNSTRON Tensile Tester (Model TT-DL) using a Type G-0l-3 Tension Cell(full-scale range 50 pounds), and the machine is set so that full-scaledeflection is obtained at 5 pounds. Two line contact jaws are used tosecure the needled sutures in the INSTRON machine. The upper jaw gripsthe needle and the lower jaw grips the suture about 0.25 inches belowthe needle. Both jaws are closed under 20 psi. air pressure. The INSTRONmachine is operated at a cross-head speed of 0.1 inches per minute and achart speed of 5 inches per minute until the tension drops to 4 ounces.

Ten prestressed needle-suture combinations randomly selected from thisproduction batch are replaced in the INSTRON machine and stressed topull the suture out of the needle. The pull-out value for each of the 10sutures is recorded below:

3.2 ounces 3.42 ounces 3.76 ounces 4.6l ounces 4.7l ounces 3.10 ounces3.70 ounces 3.25 ounces 4.12 ounces 3.15 ounces EXAMPLE 8 Size 6/0polyester suture strands are swaged to preclosed channel needlesmanufactured of 12 mil wire and having a suture engagement of sevensixty-fourths inches. The needles are swaged so that the force requiredto pull out the suture is within the range of 5 to 8 ounces.

The swaged needle-suture combinations are prestressed in a Table ModelINSTRON Tensile Tester (Model TT-DL) using a Type G-0l-3 Tension Cell(full-scale range 50 pounds), and the machine is set so that full-scaledeflection is obtained at pounds. Two line contact jaws are used tosecure the needled sutures in the lNSTRON machine. The upper jaw gripsthe needle and the lower jaw grips the suture about 0.25 inches belowthe needle. Both jaws are closed under 20 p.s.i. air pressure. TheINSTRON machine is operated at a cross-head speed of 0.1 inches perminute and a chart speed of 5 inches per minute until the tension dropsto 3 ounces.

Ten prestressed needle-suture combinations randomly selected from thisproduction batch are replaced in the INSTRON machine and stressed topull the suture out of the needle. The pull-out value for each of thesutures is recorded below:

3.05 ounces 3.10 ounces 2.51 ounces 2.75 ounces 2.35 ounces 2.70 ounces2.56 ounces 3.58 ounces 2.78 ounces 2.93 ounces EXAMPLE 9 Size 7/0 whitevirgin silk suture strands are swaged to preclosed channel needlesmanufactured of 8 mil wire (channel engagement 50 mils). The needles areswaged so that the force required to pull out the suture is within therange of 3 to 4 ounces.

The swaged needle-suture combinations are prestressed in a Table ModellNSTRON Tensile Tester (Model TT-DL) using a B Tension Cell and theassociated upper jaw (red). The instrument is calibrated with a 100 gramweight on the B cell clamp to full-scale deflection on the X-l scale.Two line contact jaws are used to secure the needled sutures in thelNSTRON machine. The upper jaw grips the needle and the lower jaw gripsthe suture about 0.25 inches below the needle. Both jaws are closedunder 20 p.s.i. air pressure. The lNSTRON machine is operated at across-head speed of 0.1 inches per minute and a chart speed of 5 inchesper minute until the tension drops to 1.8 ounces.

Ten prestressed needle-suture combinations ran domly selected from thisproduction batch are replaced in the lNSTRON machine and stressed topull the suture out of the needle. The pull-out value for each of the 10sutures is recorded below:

1.73 ounces 1.53 ounces 1.46 ounces 1.60 ounces 1.28 ounces 1.98 ounces1.40 ounces 1.39 ounces 1.82 ounces 1.77 ounces EXAMPLE 10 Size 8/0white virgin silk suture strands are swaged to preclosed channel needlesmanufactured of 8 mil wire (channel engagement 50 mils). The needles areswaged so that the force required to pull out the suture is within therange of 2 to 3 ounces.

The swaged needle-suture combinations are prestressed in a Table ModelINSTRON Tensile Tester (Model TT-DL) using a Type B Tension Cell and theassociated upper jaw (red). The instrument is calibrated with a 100 gramweight on the B cell clamp to full-scale deflection on the X-l scale.Two line contact jaws are used to secure the needled sutures in the [N-STRON machine. The upper jaw grips the needle and the lower jaw gripsthe suture about 0.25 inches below the needle. Both jaws are closedunder 20 p.s.i. air pressure. The INSTRON machine is operated at acrosshead speed of 0.1 inches per minute and a chart speed of 5 inchesper minute until the tension drops to 1.3

ounces.

Ten prestressed needle-suture combinations randomly selected from thisproduction batch are replaced in the lNSTRON machine and stressed topull the suture out of the needle. The pull-out value for each of the 10sutures is recorded below:

1.08 ounces 1.45 ounces 1.04 ounces 1 18 ounces 1.24 ounces 1.1 1 ounces1.27 ounces 1 29 ounces 1.13 ounces 1.31 ounces EXAMPLE 1 1 Size 2/0black braided silk suture strands are swaged to channel needlesmanufactured of 26 mil wire (channel engagement eleven sixty-fourthsinch). The suture ends are inserted into the needles until they are incontact with the bottom of the drilled hole as shown in FIG. 3. Theneedles are then swaged so that the force required to pull out thesuture is within the range of about from 2 to 4 pounds.

The swaged needle-suture combinations are prestressed in a Table ModellNSTRON Tensile Tester (Model TT-DL) using a Type CT Tension Cell(fullscale range pounds), and the machine is set so that full-scaledeflection is obtained at 20 pounds. Two line contact jaws are used tosecure the needled sutures in the INSTRON machine. The upper jaw gripsthe needle and the lower jaw grips the suture about 0.25 inches belowthe needle. Both jaws are closed under 20 p.s.i. air pressure. ThelNSTRON machine is operated at a cross-head speed of 0.1 inches perminute and a chart speed of 5 inches per minute until the stress dropsto 14 ounces.

Ten prestressed needle-suture combinations randomly selected from thisproduction batch are replaced in the lNSTRON machine and stressed topull the suture out of the needle. The pull-out value for each of the 10sutures is recorded below:

8 ounces 1 1 ounces 16 ounces 13 ounces 9 ounces 13 ounces 10% ounces 12ounces 1 1 ounces 14 ounces The needle-suture combinations of thepresent invention may be used by the surgeon employing conven tionalsuturing technique as illustrated in FIG. 1. After the suture has beenplaced, the needle may be separated by a wrist motion snapping theneedle off the end of the suture as best illustrated in FIG. 2. Theforce required to pull the needle from the end of the suture is relatedto the suture size and is in the range of from about 1 ounce to about 26ounces.

What is claimed is:

1. [n a method of manufacturing a swaged needle suture combinationcomprising a needle having pointed and blunt ends, said needle having anopening in the blunt end thereof and a suture, one end of which isreceived within said opening, the improvement comprising pre-stressingthe suture with respect to said needle by applying sufiicient tension tothe suture to move it relative to said needle; and releasing the tensionwhen the force drops to a value within the following range for 2. Aswaged needle-suture combination comprising a needle having pointed andblunt ends, said needle having an opening in the blunt end thereof and asuture, one end of which is received within said opening said suturebeing pre-stressed with respect to said needle so that the suture isdisplaced from the inner end of said opening whereby the suture may bepulled out of the needle by a force that is within the following rangefor that size of suture Suture Size Ounces 8/0 l. 2. 7/0 l. 3. 6/0 2. 5./0 3. 7. 4/0 3. l5. 3/0 3. 23. 2/0 3. 26. H0 l0. 26.

l 10. 26. 2 and larger 10. 26.

3. The needle-suture combination of claim 2, wherein the suture isdisplaced from the inner end of the opening a distance of about 0.08inches.

4. The needle-suture combination of claim 2, wherein the suture isdisplaced from the inner end of the opening a distance of about 42 to 50per cent of the length of said opening.

5. The needle-suture combination of claim 2, wherein the needle is adrilled needle.

6. The needle-suture combination of claim 2, wherein the needle is achannel needle.

7. The needle-suture combination of claim 2, wherein the suture is acovered silk suture.

8. The needle-suture combination of claim 2, wherein the suture is abraided polyester suture.

9. The needle-suture combination of claim 8, wherein said polyester ispolyhydroxyacetic ester.

10. The needle-suture combination of claim 8, wherein said polyester isa copolymer of glycolide and L(-) lactide.

11. The needle-suture combination of claim 2, wherein the suture is abraided nylon suture.

12. The needle-suture combination of claim 2, wherein the suture is abraided suture.

13. The needle-suture combination of claim 2, wherein the suture is abraided silk suture.

14. The needle-suture combination of claim 2, wherein the suture is amonofilament.

15. The needle'suture combination of claim 2, wherein the needle is acurved needle.

16. The I needle-suture combination of claim 2, wherein the needle is astraight needle.

17. The needle-suture combination of claim 2, wherein the needle is acutting edge needle.

18. The needle-suture combination of claim 2,

wherein the needle is a taper point needle.

* ll t

1. In a method of manufacturing a swaged needle-suture combinationcomprising a needle having pointed and blunt ends, said needle having anopening in the blunt end thereof and a suture, one end of which isreceived within said opening, the improvement comprising pre-stressingthe suture with respect to said needle by applying sufficient tension tothe suture to move it relative to said needle; and releasing the tensionwhen the force drops to a value within the following range for that sizeof suture
 2. A swaged needle-suture combination comprising a needlehaving pointed and blunt ends, said needle having an opening in theblunt end thereof and a suture, one end of which is received within saidopening said suture being pre-stressed with respect to said needle sothat the suture is displaced from the inner end of said opening wherebythe suture may be pulled out of the needle by a force that is within thefollowing range for that size of suture
 3. The needle-suture combinationof claim 2, wherein the suture is displaced from the inner end of theopening a distance of about 0.08 inches.
 4. The needle-suturecombination of claim 2, wherein the suture is displaced from the innerend of the opening a distance of about 42 to 50 per cent of the lengthof said opening.
 5. The needle-suture combination of claim 2, whereinthe needle is a drilled needle.
 6. The needle-suture combination ofclaim 2, wherein the needle is a channel needle.
 7. The needle-suturecombination of claim 2, wherein the suture is a covered silk suture. 8.The needle-suture combination of claim 2, wherein the suture is abraided polyester suture.
 9. The needle-suture combination of claim 8,wherein said polyester is polyhydroxyacetic ester.
 10. The needle-suturecombination of claim 8, wherein said polyester is a copolymer ofglycolide and L(-) lactide.
 11. The needle-suture combination of claim2, wherein the suture is a braided nylon suture.
 12. The needle-suturecombination of claim 2, wherein the suture is a braided suture.
 13. Theneedle-suture combination of claim 2, wherein the suture is a braidedsilk suture.
 14. The needle-suture combination of claim 2, wherein thesuture is a monofilament.
 15. The needle-suture combination of claim 2,wherein the needle is a curved needle.
 16. The needle-suture combinationof claim 2, wherein the needle is a straight needle.
 17. Theneedle-suture combination of claim 2, wherein the needle is a cuttingedge needle.
 18. The needle-suture combination of claim 2, wherein theneedle is a taper point needle.